Diff: targets/TARGET_NXP/TARGET_LPC15XX/i2c_api.c

Revision:

149:156823d33999

Parent:

144:ef7eb2e8f9f7

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/targets/TARGET_NXP/TARGET_LPC15XX/i2c_api.c	Fri Oct 28 11:17:30 2016 +0100
@@ -0,0 +1,217 @@
+/* mbed Microcontroller Library
+ * Copyright (c) 2006-2013 ARM Limited
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+#include "mbed_assert.h"
+#include "i2c_api.h"
+#include "cmsis.h"
+#include "pinmap.h"
+
+static uint8_t repeated_start = 0;
+
+#define I2C_STAT(x)         ((LPC_I2C0->STAT >> 1) & (0x07))
+
+static inline int i2c_status(i2c_t *obj) {
+    return I2C_STAT(obj);
+}
+
+// Wait until the Serial Interrupt (SI) is set
+static int i2c_wait_SI(i2c_t *obj) {
+    volatile int timeout = 0;
+    while (!(LPC_I2C0->STAT & (1 << 0))) {
+        timeout++;
+        if (timeout > 100000) return -1;
+    }
+    return 0;
+}
+
+static inline void i2c_interface_enable(i2c_t *obj) {
+    LPC_I2C0->CFG |= (1 << 0);
+}
+
+void i2c_init(i2c_t *obj, PinName sda, PinName scl) {
+    MBED_ASSERT((sda == P0_23) && (scl == P0_22));
+    
+    // Enables clock for I2C0
+    LPC_SYSCON->SYSAHBCLKCTRL1 |= (1 << 13);
+
+    LPC_SYSCON->PRESETCTRL1 |=  (1 << 13);
+    LPC_SYSCON->PRESETCTRL1 &= ~(1 << 13);
+
+    // pin enable
+    LPC_SWM->PINENABLE1 &= ~(0x3 << 3);
+
+    // set default frequency at 100kHz
+    i2c_frequency(obj, 100000);
+    i2c_interface_enable(obj);
+}
+
+inline int i2c_start(i2c_t *obj) {
+    int status = 0;
+    if (repeated_start) {
+        LPC_I2C0->MSTCTL = (1 << 1) | (1 << 0);
+        repeated_start = 0;
+    } else {
+        LPC_I2C0->MSTCTL = (1 << 1);
+    }
+    return status;
+}
+
+inline int i2c_stop(i2c_t *obj) {
+    volatile int timeout = 0;
+
+    LPC_I2C0->MSTCTL = (1 << 2) | (1 << 0);
+    while ((LPC_I2C0->STAT & ((1 << 0) | (7 << 1))) != ((1 << 0) | (0 << 1))) {
+        timeout ++;
+        if (timeout > 100000) return 1;
+    }
+
+    return 0;
+}
+
+
+static inline int i2c_do_write(i2c_t *obj, int value, uint8_t addr) {
+    // write the data
+    LPC_I2C0->MSTDAT = value;
+    
+    if (!addr)
+        LPC_I2C0->MSTCTL = (1 << 0);
+    
+    // wait and return status
+    i2c_wait_SI(obj);
+    return i2c_status(obj);
+}
+
+static inline int i2c_do_read(i2c_t *obj, int last) {
+    // wait for it to arrive
+    i2c_wait_SI(obj);
+    if (!last)
+        LPC_I2C0->MSTCTL = (1 << 0);
+    
+    // return the data
+    return (LPC_I2C0->MSTDAT & 0xFF);
+}
+
+void i2c_frequency(i2c_t *obj, int hz) {
+    // No peripheral clock divider on the M0
+    uint32_t PCLK = SystemCoreClock;
+    uint32_t clkdiv = PCLK / (hz * 4) - 1;
+    
+    LPC_I2C0->DIV = clkdiv;
+    LPC_I2C0->MSTTIME = 0;
+}
+
+int i2c_read(i2c_t *obj, int address, char *data, int length, int stop) {
+    int count, status;
+    
+    i2c_start(obj);
+    
+    LPC_I2C0->MSTDAT = (address | 0x01);
+    LPC_I2C0->MSTCTL |= 0x20;
+    if (i2c_wait_SI(obj) == -1)
+        return -1;
+
+    status = ((LPC_I2C0->STAT >> 1) & (0x07));
+    if (status != 0x01) {
+        i2c_stop(obj);
+        return I2C_ERROR_NO_SLAVE;
+    }
+    
+    // Read in all except last byte
+    for (count = 0; count < (length - 1); count++) {
+        if (i2c_wait_SI(obj) == -1)
+            return -1;
+        LPC_I2C0->MSTCTL = (1 << 0);
+        data[count] = (LPC_I2C0->MSTDAT & 0xFF);
+        status = ((LPC_I2C0->STAT >> 1) & (0x07));
+        if (status != 0x01) {
+            i2c_stop(obj);
+            return count;
+        }
+    }
+    
+    // read in last byte
+    if (i2c_wait_SI(obj) == -1)
+        return -1;
+
+    data[count] = (LPC_I2C0->MSTDAT & 0xFF);
+    status = i2c_status(obj);
+    if (status != 0x01) {
+        i2c_stop(obj);
+        return length - 1;
+    }
+    // If not repeated start, send stop.
+    if (stop) {
+        i2c_stop(obj);
+    } else {
+        repeated_start = 1;
+    }
+    
+    return length;
+}
+
+int i2c_write(i2c_t *obj, int address, const char *data, int length, int stop) {
+    int i, status;
+    
+    i2c_start(obj);
+    
+    LPC_I2C0->MSTDAT = (address & 0xFE);
+    LPC_I2C0->MSTCTL |= 0x20;
+    if (i2c_wait_SI(obj) == -1)
+        return -1;
+
+    status = ((LPC_I2C0->STAT >> 1) & (0x07));
+    if (status != 0x02) {
+        i2c_stop(obj);
+        return I2C_ERROR_NO_SLAVE;
+    }
+    
+    for (i=0; i<length; i++) {
+        LPC_I2C0->MSTDAT = data[i];
+        LPC_I2C0->MSTCTL = (1 << 0);
+        if (i2c_wait_SI(obj) == -1)
+            return -1;
+
+        status = ((LPC_I2C0->STAT >> 1) & (0x07));
+        if (status != 0x02) {
+            i2c_stop(obj);
+            return i;
+        }
+    }
+    
+    // If not repeated start, send stop.
+    if (stop) {
+        i2c_stop(obj);
+    } else {
+        repeated_start = 1;
+    }
+    
+    return length;
+}
+
+void i2c_reset(i2c_t *obj) {
+    i2c_stop(obj);
+}
+
+int i2c_byte_read(i2c_t *obj, int last) {
+    return (i2c_do_read(obj, last) & 0xFF);
+}
+
+int i2c_byte_write(i2c_t *obj, int data) {
+    if (i2c_do_write(obj, (data & 0xFF), 0) == 2) {
+        return 1;
+    } else {
+        return 0;
+    }
+}